So, here it all comes. As of Monday, the spare bedroom tax is not merely the subject of highly charged radio phone-ins, but blunt reality. The same goes for alterations to council tax benefit, and the overlooked change whereby the Department for Work and Pensions' discretionary social fund is no more.

The period for the 1% cap on increases to working-age benefits starts in five days' time, and next week the DWP will begin the transition from disability living allowance to the personal independence payment. The government hopes to save £2bn, largely by denying up to 500,000 people the new benefit. From 15 April the across-the-board annual benefits cap of £26,000 will be piloted in four London boroughs. And all the time, the dawn of universal credit – due in October – looms, amid plenty of signs of hubris and ineptitude leading to disaster.

Food banks are anticipating a surge in demand, and worrying about their capacity to cope. Churches are up in arms, as evidenced by a recent intervention by Anglican bishops, and the weekend's protests from Baptists, Methodists, the Church Of Scotland and the United Reformed Church. Loudest of all is a great chorus of lefty ire – perhaps lacking when the reforms were making their way through parliament, but now in full effect. The usual rules apply: the whole thing is a conspiracy by the Tories and their allies in the media; Labour most not be gripped by the disease of Blairite betrayal; it is time for charters, and demonstrations and, if things get sticky, multi-signatory letters to the liberal-left media, so as to really put the wind up them.

At which point, some polling numbers, just as crude and blunt as the changes themselves. According to ComRes, 64% of Britons believe the benefits system either does not work well or is "failing", and 40% of us think that at least half of all benefit recipients are "scroungers". Ipsos Mori reckons 84% of its respondents either agree or tend to agree with stricter work-capability tests for disabled people, and 78% are in accord with the idea that benefits should be docked if people turn down work that pays the same or less than they get in benefits.

The same research suggests 62% are OK with the idea of benefits being capped "if people choose to have more children", and 57% agree with the essential logic of capping housing benefit. When it comes to big-picture stuff, a majority of us seem to believe in the notion of welfare dependency (once a controversial trope peddled by the nasty Tory right, but now as firmly built into the public consciousness as the idea that the poor spend too much of their money on booze, fags and Sky TV). It may be a cliche to suggest that tens of millions of people have precious little objection to what Iain Duncan Smith is up to, but that does not make it any less true.

As yet another poll – by YouGov, commissioned by the TUC – proved last year, people seem to hold wildly inaccurate views about the scale of benefit fraud and the proportion of spending that goes on people who cannot find work, and more. But in three years of regularly asking people what they think about the welfare state, I have never heard a single voice echoing the bien-pensant – and factually accurate – view that benefit fraud accounts for a tiny share of social security spending. Instead, people think it is a real, urgent problem, and everyone claims to know someone who does it.

In Warrington, Liverpool, Hartlepool, Peterborough and many other places, I have heard much the same stuff, and two rules always apply. First, as against the idea that disaffection with the benefits system amounts to a petit bourgeois roar from the suburbs, a lot of the noise gets louder as you head into the most disadvantaged parts of society. Second, it is the under-30s who have the most severe perspective of all. Polling bears this latter point out: in the aforementioned ComRes poll, the share of those aged 18-34 who thought a half or more of people on benefits were "scroungers" outstripped that of all other age groups by nearly 10 percentage points.

Much of this strain of public sentiment has always been with us, though in the days when one-nation Toryism was still thriving, and the Labour-voting working class could just about be understood as a coherent and united political entity, politicians tended to avert their eyes from it. But with all that long gone, the politics of so-called welfare now falls one of two ways: centre-left politicians catch glimpses of public opinion and stay frozen to the spot, while the right endlessly seizes its chance.

Any kind of textured conversation has yet to start. No one, on the left or right, has much to say about how distant the benefits system is from our ongoing skills crisis, and the idea that people who cannot find work may well be in need of training and education, rather than incessant nudges towards the bottom of the labour market. The undeveloped idea of a more contributory system is probably the only way out of the mess, and a useful means of highlighting the grimness of what is happening. I have met many victims of the government's cruelties who have dutifully paid national insurance for most of their adult lives, only to be kicked around beyond endurance – and these voices need to get much louder.

There is still a huge problem with language, and the ubiquity of the hopelessly loaded term "welfare". Last week the Unite union launched a website called Our Welfare Works, and thus stumbled at the start. Meanwhile, the entry of the church into the debate may or may not mark a watershed point, as we begin to find out whether Duncan Smith has overreached himself. Like the Anglicans, Methodists and the rest, I will be praying he has. But don't count on it.